A study of rust layer of low alloy structural steel containing 0.1 % Sb in atmospheric environment of the Yellow Sea in China

The rust layer formed on the Sb-containing Steel in the atmospheric environment of the Yellow Sea and its benefit for corrosion resistant was studied. The effect of Sb on the corrosion mechanism of rust layer was analysed. The cross section of rust layer was examined by SEM, and the effect of Sb on the evolution of rust layer of low alloy steel was studied using XRD, XPS, Raman, LCM and polarization curves. It found that rust layer formed on the Sb-containing Steel has the better structure and phase composition than that on Sb-free Steel. Sb can consume H+ and alleviate the local acidization on the surface of the steel, and also accelerate the transformation of gamma-FeOOH to Fe3O4 in rust layer. The corrosion product of Sb, a stable Sb2O3, together with Fe3O4, make the rust layer more uniform and compact, thus more effective to resist the corrosive ions.